Collector ring and brush assembly



COLLECTOR RING AND BRUSH ASSEMBLY Filed Aug.. 29, 1942 mL/AM Euoooc/c,

INVENTOR.

ATTORNEY.

4% w y I Patented Feb. 25, 1947 UNITED STATES PATENT OFFICE COLLECTOR RING AND BRUSH ASSEMBLY William Ruddock', South. Pasadena, Calif., as-

signor, by direct. and mesne assignments,- to The McCatfrey Ruddoclr.;Tagl-ine Corporation, Los Angeles, Caliil, a corporation of California Application August 29, 1942, Serial No. 456,593

5 Claims (Cl. 173-324) plied with current through a long flexible cable.

Lifting is of course controlled by opening and closing the magnetic circuit. When a reel is used for winding up the electrical cable it is necessary to provide some means for connecting the cable to a source of current supply. In my co-pending application I showed a pair of slip rings for connecting a cable on the magnet to a source of current supply. I have found that the ordinary slip ring employing a single brush is severely limited in its application.

The primary reason for the unsatisfactory operation of slip rings and brushes in a structure of this type is the fact that the tagline structure is ordinarily supported on the: boom of the derrick.

. The shocks. and jars to which the boom is subiected by the lifting and dropping of the load,

by sudden stopping of the load in downward movement, y the striking of the magnet on the:

It is a further object of the present invention to provide a slip ring mechanism which is equally the brushes andthe slip rings. In fact, if the magnet is permitted to drop freely while it is loaded and is suddenly brought to a halt by the application of. the brake, the brushes; can leave the slip rings for a sufiicient length of time to cause the magnet to drop its load, which also violently agitatesthe boom and causes further. sparking or arcing at the slip ring. The slip ring and brushes thus, losetheir eiliciency and, the pits re sulting from the sparking, tend to aggravate this condition until the slip ring is'so badly pitted that it will not effectively carry suflicient current to the brushes. It can be seen that such a situation is extremely dangerous and the operator can not then be sure that the magnet will continue to support the load until he shuts oil the current;

I v With the above disadvantages and difii'culties' inmind, it is an object of the present invention effective in all positions;

This invention possesses many other-advantages and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown a. form in the drawings accompanying and forming part of the present specification. This form will'now be described in detail, illustrating the general principles of the invention; but it is to bev understood that this detailed description is not to be taken in a limiting sense, since the scope: of the invention is best defined by the appended claims.

Referring now to the drawings:

Figure 1 is a general side view of the device involving the present invention installed on a crane;

Figure 2 is an enlarged fragmentary sectional View taken on line 22 of Figure 1;

Figure 3 is a still further enlarged sectional part of the structure shown in Figur 2; and I Figure 4 is a section taken on line 4-4 of Figure 2-.

In Figure 1 there is shown a derrick or crane having a boom l0, and supporting a lifting magnet H. In order to prevent the. hoisting lines I2 from crossing, and also to preserve thecable from mechanical harm, a tagline I3 is secured to the magnet H and is wound upon av reel IL, This reel [4, in addition to keeping the tagline I3 taut, also serves to wind the magnet cable 15. The magnet H is thus. kept from spinning and the cable I5 is protected from undue tension and is prevented from dragging upon the ground.

The reel I4 is spring driven, as was fully explained in my co -pending application, Serial and a similar stud 22 passing through another portion of the flange are threaded into the collector rings 23 and 24 respectively. These studs thus form electrical terminals by which the ends of the magnet cable I-iare attached to the collector rings. The collector rings 23 and:- 2.4 are insulated; from each other and from the rest of An insulated stud 2i! passing through the flange 2| the structure by an interior tube 25 and discs 26 and 21 formed of insulating material.

A cover 28 is secured to the spring housing [6 by bolts 28a, and serves to protect the collector rings and brushes from dirt and mechanical damage. Mounted on this cover 28 is a bolt 29 which serves as a support for the brush holders. As can be seen by referring to Figures 3 and 4, each collector ring engages a pair of brushes 30 and 3|, which are electrically connected together and thus form in effect a single brush. However, they are supported on arms 32 and 33- respectively, which are pivoted together on the bolt 29 and are mechanically freely movable with respect to each other. A spring 34 furnishes the necessary pressure" to hold the brushes on the slip ring. As can be seen, this spring is simply a generally rectangular loop of wire with eyes 34a formed in its longer sides to pass around the bolt 29, the short sides of the rectangle engaging the outer periphery of the brush holder arms and tending to force them'toward each other.

Both sets of brushes are identical so far as mechanical structure is concerned and the set of brushes on the slip ring 33 will not be further described.

It can be seen from the drawing that the bolt 29 isfastened to the boom so that a line drawn through the center of the shaft I8 and parallel to the axis of the boom passes through the bolt 29. This being so, the centers of thearcs of contact of the brushes fall on a line perpendicular "to the axis of the boom. It will be understood that the line passing through the centers of the 35 arcs of contact of the brushes need not be absolutely perpendicular to the axis of the boom, but the angle between'this line and the axis of the boom should be a substantial one for the best results. I

When a load is dropped, or when the device is so operated that a sudden strain is placed on the load carrying magnet, e. g., if the. brake is suddenly applied during downward movement of the magnet, very violent oscillations are set up in the boom. Such oscillation results in acceleration of the boom in the directions indicated by the full and dotted arrows of Figure 4. A downward acceleration of the boom will cause the brush 3!] to tend to leave the collector ring. The

same acceleration, however, will tend to press the brush 3! more firmly against the collector ring.

In addition to this, if the brush 30 actually leaves the collector ring, it will flex the spring34 in such a manner as to more tightly press the brush 3! against the collector ring. If the acceleration is in an upward direction it is-the lower brush 3| which tends to leave the collector ring and the upper brush 30 which is more tightly pressed against the ring.

The low resistance in the short lead 40 connecting the two brushes of each pair assures that if one brush of a pair leaves the collector ring there will be no arcing, as one brush is sufficient to carry the entire magnetizing current.

' In actual practice it has been found that the use of a pair of brushes arranged in the fashion described eliminates entirely arcing between the 'brushes and the ring, and the load is never 'dropped because the brushes.

f the opening of the circuit at I claim: 7

1. In a conductor and brush assembly adapted for use on a structure having a principal plane of vibration a support; a rotary conducting mem 4 her, a pair of brushes, means pivotally supporting said brushes on said support for independent movement toward and away from said member in substantially opposite directions substantially whereby said brushes are adapted to clasp said member by engaging areas on substantially opposite sides thereof, and resilient means mounted independently of said support and connected between said brushes for simultaneously urging them toward said member.

2. A conductor and brush assembly adapted for use on a structure having a principal plane of vibration, comprising a member providing a curved conducting surface. rotatable about an axis substantially normal to an element of said plane extending in the direction of said vibration, a pair of brushes adapted to contact respectively areas on said surface adjacent the opposite ends of a diameter of said surface, means forming a common pivotal support for said brushes, whereby said brushes are independently movable toward and away from said conducting surface in a plane parallel with said element, and resilient means connecting said brushes for simultaneously urging them toward said surface.

3. A collector and brush assembly comprising, a support, a member adjacent said support having a cylindrical conducting surface, said support and said member being subject to sudden relative vibratory movement along a line substantially perpendicular to the axis of said member, a brush holder having a pair of arms disposed one on each side of the cylindrical surface of said member, a pair of brushes mounted respectively on said arms and ,engaging the cylindrical surface of said member at points on said line substantially diametrically opposed with respect'to said cylinder,

means movably mounting said holder on said support effective to permit movement of said brushes with respect to said support substantially along said line, and means effective to bias said brushes against the cylindrical surface of said member.

Y 4. A collector and brush assembly comprising,

a support, a member-adjacent said support, said support and said member being subject to sudden relative vibratory movement along a line substantially perpendicular to the axis of said member, a brush holder having a pair of arms'disposed one on each sideof said member, a pair of brushes mounted respectively on said arms and engaging said member at points on said line subv stantially diametrically opposed-with respect to brush holder having a pair of arms disposed one 7 on each side .of said member; a pair of brushes mounted respectively on said arms-and engaging said member at points on said line substantially diametrically opposed with respect to saidmem- .ber; means mounting aid holder onsaid support .pivqtally about an axis parallel tothe axisof said member and spacedv appreciably away fromsaid parallel with an element of said plane extending in the direction in which said vibration acts 5 r 6 member, and effective to permit movement of said brushes with respect to said support substan- UN S AT S PATENTS tially along said line; and means efiective to bias Number m Date said brushes toward said member. 2,242273 Taylerson May 20, 1941 5 2,204,325 Staley June 11, 1940 RUDDOCK- 2,309,316 Hollander Jan. 26, 1943,

REFERENCES CITED FOREIGN PATENTS The following references are of record in the Number Country I Date file of this patent: 10 11,758 British 190s 

